The first child known to be screened as an embryo for the BRCA-1 gene, which often causes breast and ovarian cancer, was born in Britain this week, raising new ethical questions about genetic screening.

A University College London spokesman told CNN that the girl was screened through pre-implantation genetic diagnosis, which tests a group of embryos created through in vitro fertilization when each contains eight cells. The cells are tested, and only ones free of the BRCA-1 gene are returned to the womb.

Doctors around the world already test for genes that definitely cause illnesses like cystic fibrosis or Huntington's Disease, but this is the first time an infant is known to have been tested as an embryo for a gene that is only likely to cause disease. People with the BRCA-1 gene have a 50-80 percent chance of developing breast or ovarian cancer in their lifetimes. Though the British press is calling her the "cancer-free" girl, she could still develop a non-genetic form of the cancers.

Soon doctors will be able to test for other forms of cancer, including a forms of bowel cancer and cancer of the retina. Testing for diseases that may not be fatal and may not appear for decades has raised ethical questions that once seemed like science fiction. "This is simply a mechanism for eliminating the birth of anybody (prone to) the disease," said Josephine Quintavalle, co-founder of the group Comment on Reproductive Ethics, who says the fact that disease carrying embryos are often discarded is essentially murder. "The message we are sending is: 'Better off dead than carrying (a gene linked to) breast cancer,'" she said.

Peter Braude, a top British expert on the genetic testing of embryos, says that he sees the procedure as a way to prevent abortions because it is performed on a three-day old embryo that hasn't been implanted. Rather than testing embryos, couples can conceive naturally and test the fetus weeks into pregnancy, at which point some couples choose to abort when the test finds a genetic defect.

The Human Fertilisation and Embryology Authority was established in 1990 in Britain to determine which conditions geneticists can test for, but a similar agency does not exist in the United States. Dr. Mark Hughes, who founded a genetics clinic in Detroit that performs about two tests per month for the breast cancer gene, says he likes the idea of a regulatory agency like Britain's. However, he thinks parents should be allowed to test for genetic abnormalities, especially in families that have been hit again and again by a disease. "You can get up on your high horse and say people are looking for perfect children, but let's give these families more credit," said Hughes. "They just want one that has a fighting chance of not having a disease."